14. OCEANODROMA MONORHIS (Swinhoe). 



(SWINHOE'S FORK-TAILED PETREL.) 



(Plate 9.) 



Thalassidroma monorhis, Swinhoe, Ibis, 1867, p. 386. 

 Procellaria monorhis, Gray, Handl. Birds, III., p. 104, No. 10,855 (1871). 

 Oceanodroma monorhis, Salvin, Cat. Birds Brit. Mus., XXV., p. 121, PI. II. (1896). 

 Oceanodroma socorroensis, C. H. Townsend, Pr. U. S. Nat. Mus., XIII. , p. 134 (1890) ; 



Salvin, Cat. Birds Brit. Mus., XXV., p. 352 (1896); Anthony, Auk, 1896, p. 387, 



1898, p. 38 ; Oates, Cat. Eggs Brit. Mus., I., p. 149, PI. XL, Fig. 6 (1899) ; 



Grinnell and Daggett, Auk, 1903, p. 31 ; Godman, Biol. Centr.-Amer., Aves, 



III., p. 431 (1904). 

 Oceanodroma toivnsendi (nee Ridgway), Anthony, Auk, 1904, p. 321. 

 Oceanodroma monorhis chapmani, Berlepsch, Auk, 1906, p. 185. 



O. melanice similis, sed minor : pileo et corpore autico magis plumbescentibus. 



The Storm-Petrel hitherto known as O. socorroensis is a small form of O. melania, 

 and it is somewhat remarkable that the two races should be found inhabiting the same 

 localities, both breeding on the San Benito and Coronado Islands. There is scarcely 

 any difference beyond that of measurements between 0. melania and O. socorroensis, 

 but the latter is perhaps imbued with a more plumbeous shade on the head, neck, and 

 forepart of the body, the face and throat being also plumbeous. O. melania, on the 

 other hand, is a very black bird, and is decidedly larger than O. socorroensis, as the 

 measurements show. 



The series of 0. melania examined by me gives the following results : — 



a. b. c?San Benito Isl. (Mus. Rothschild) 



c. d. ? Do. do. 



e. <$ Do. (Mus. Brit.) 



f. g. ? Do. do. 



32 



Wing. 



Tarsus. 



Middle toe 

 and claw. 



6.7-7.0 . 



. 1.15-1.2 . 



1.2 



6.9-7.2 . 



. 1.15-1.2 . 



1.2 



6.8 



. 1.15 



1.1 



6.9-7.0 . 



. 1.2 



1.1 



